Street-pavement



UNITED STATES ATENT FFICE.

HUGH B. ALEXANDER, OF GENEVA, ILLINOIS.

STREET-PAVEMENT.

SPECIFICATION forming part of Letters Patent No. 438,046, dated October '7, 1890.

Application filed May 19, 1890. Serial No. 352.893- (No model.)

To all whom it may concern:

Be it known that I, HUGH B. ALEXANDER, a citizen of the United States, residing at Geneva, in the county of Kane and State of Illinois, have invented a new and useful Street- Pavement, of which the following is a specification.

My invention relates to street-pavements, with particular reference to the material of the foundation upon which to place the wearin g-surface.

The object of this invention is to provide a foundation similar to concrete from material common to most sections of the country, inexpensive and readily laid down by unskilled labor, and to provide a foundation fully as durable as concrete, but far more elastic and impervious tofrost.

The material that I use for my foundation is burnt claysuch as is ordinarily manufactured for ballasting railroads-and this substance when compacted forms a homogeneous mass free from organic matter, elastie, a non-conductor of heat, and forms a bed that is comparatively noiseless.

In laying down the pavement I first reduce the roadway to the proper sub-grade, compacting with ordinary road-roller, when necessary. I then spread a layer of large fragments of burnt clay over this surface to a depth of four or five inches and firmly roll the same with the roller. The fragments of burnt clay are Very irregular and jagged in shape, and when pressed together by heavy pressure, as with a road-roller, the entire mass knits together and forms a continuous sheet similar to a concrete foundation, but with the advantages specified. After the large fragments have been pressed into a homogeneous mass I then spread thereupon a layer of smaller fragments or screenings to a depth of two or three inches. This stratum 0f screenings is slightly moistened from a sprinkling cart or hose and the roller is applied as before. If required, a third layer of still finer screenings may be applied and rolled after moistening. This process being completed, the surface has the appearance, as said, of a concrete foundation and will bear up heavy-rolling loads without damage; but the disintegration made by horses feet striking obliquely upon it scale it OE, and mud and other refuse mixed with it would naturally cause deterioration to set in, as is also the case with concrete under similar treatment. I therefore use the burnt clay only as a foundation for a reliable wearingsurfacesuch as paving-brick, wooden, stone, or other blocks, or sheet asphalt. However, I prefer vitrified paving-brick because of its many good qualities, and especially because of its general availability where burnt clay can be manufactured, thus producing all the materials for street-pavement from a single clay-bank.

Before putting down the wearing-surface when a block or brick is used, I spread a thin layerof burnt-clay screenings or pulverized burnt clay over the prepared foundation in which to bed the blocks. I then lay down the blocks or bricks in the usual manner adapted for each kind of material, using, however, only one course of brick when that material is used for a wearing-surface. I then tamp into the joints and interstices between the blocks burnt-clay screenings, finishing with hot tar or other similar composition to prevent access of Water to the interior. This latter process is not essential, as the water freely passes through the foundation to the sub-grade below, and is carried off by the drains without damage to the road- Way.

The pulverized burnt clay has strong bydraulic cementing qualities, and as the burnt clay is usually prepared with coal-slack as a fuel, quite a large percentage of ashes results, which also acts as a cementing material in combination with the clay, and the result from the use thereof is an impervious, elastic, and durable pavement.

Having thus described my invention, the construction of the pavement, and the materials used, what I claim, and desire to secure by Letters Patent, is-

In a street-pavement, the combination of burnt-clay fragments as a foundation, a thin layer of burnt-clay screenings or pulverized burnt clay for bedding the wearing-surface, with the same material tamped into the joints or interstices of the block or bricks composing the Wearing-surface, substantially as described.

- In testimony that I claim the foregoing as my own I have hereto affixed my signature in presence of two witnesses.

-. HUGH B. ALEXANDER.

Witnesses:

J. M. KENNEDY, M. G. STECK. 

